SAN FRANCISCO, CA - JUNE 26: Madison Bumgarner #40 of the San Francisco Giants pitches against the Cleveland Indians in the second inning during a MLB baseball game at AT&T Park June 26, 2011 in San Francisco, California.

Photo: Thearon W. Henderson, Getty Images

SAN FRANCISCO, CA - JUNE 26: Madison Bumgarner #40 of the San...

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SAN FRANCISCO, CA - JUNE 26: Aubrey Huff #17 of the San Francisco Giants hits a RBI single against the Cleveland Indians in the bottom of the third inning during a MLB baseball game at AT&T Park June 26, 2011 in San Francisco, California.

Photo: Thearon W. Henderson, Getty Images

SAN FRANCISCO, CA - JUNE 26: Aubrey Huff #17 of the San Francisco...

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San Francisco Giants pitcher Madison Bumgarner throws to the Cleveland Indians during the first inning of a baseball game Sunday.

Photo: George Nikitin, AP

San Francisco Giants pitcher Madison Bumgarner throws to the...

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Cleveland Indians' Grady Sizemore drops a fly ball hit by San Francisco Giants pitcher Madison Bumgarner during the fourth inning of a baseball game, Sunday, June 26, 2011 in San Francisco.

Photo: George Nikitin, AP

Cleveland Indians' Grady Sizemore drops a fly ball hit by San...

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San Francisco Giants Cody Ross (13) is greeted in the dugout after scoring against the Cleveland Indians during the second inning.

Photo: George Nikitin, AP

San Francisco Giants Cody Ross (13) is greeted in the dugout after...

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San Francisco Giants' Bill Hall, right, rounds third base past Giants third base coach, Tim Flannery, during the second inning of a baseball game against the Cleveland Indians, Sunday. Hall and teammate Cody Ross both scored on Chris Stewart's hit.

Photo: George Nikitin, AP

San Francisco Giants' Bill Hall, right, rounds third base past...

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Pablo Sandoval #48 of the San Francisco Giants tags out Grady Sizemore #24 the Cleveland Indians attempting to steal third in the second inning.

Photo: Thearon W. Henderson, Getty Images

Pablo Sandoval #48 of the San Francisco Giants tags out Grady...

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Bill Hall #6 of the San Francisco Giants slides home safe on a two RBI double by Chris Stewart #37 against the Cleveland Indians in the bottom of the second inning.

Photo: Thearon W. Henderson, Getty Images

Bill Hall #6 of the San Francisco Giants slides home safe on a two...

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Cody Ross #13 of the San Francisco Giants rounds third base to score on a two RBI double by Chris Stewart #37 against the Cleveland Indians in the bottom of the second.

Photo: Thearon W. Henderson, Getty Images

Cody Ross #13 of the San Francisco Giants rounds third base to...

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Bill Hall #6 of the San Francisco Giants gets caught in a rundown between third and home and is tagged out by Carlos Santana #41 of the Cleveland Indians in the bottom of the fourth inning.

Photo: Thearon W. Henderson, Getty Images

Bill Hall #6 of the San Francisco Giants gets caught in a rundown...

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Cleveland Indians' Shelley Duncan takes off his helmet after striking out with two runners on base against the Giants.

-- Madison Bumgarner did not have to prove his mettle to anybody. He checked that box in indelible ink when he pitched eight shutout innings in his first World Series start as a 21-year-old rookie.

If any skeptics remained, Bumgarner gave them Exhibit B on Sunday night, when he overcame his historically bad start against Minnesota by going on national television, striking out a career-high 11 and holding Cleveland to one run over seven innings in a 3-1 Giants victory.

"He's a big kid with a good head on his shoulders," reliever Jeremy Affeldt said. "This is bigger than just a good outing for him. This is big for his maturity. I'm sure everyone from the coaching staff to the manager is proud of him."

When Affeldt struck out five of his six hitters to complete a two-inning save - Brian Wilson was tethered to the bench after four straight appearances - the Giants completed a three-game sweep that knocked the Indians out of first place in the American League Central.

The Giants have swept four three-game series this season without scoring more than 10 runs in any of them.

They also won their fifth consecutive game to cover a five-game losing streak that preceded it.

The fifth loss came Tuesday, when Bumgarner retired one batter and allowed nine hits and eight runs.

Manager Bruce Bochy and several Giants said they knew Bumgarner would respond with a winner. Catcher Chris Stewart, whose two-run double in the second inning supplied the necessary support, said Bumgarner "came in tonight to dominate, and that's what he did."

Only Bumgarner was not 100 percent sure of himself.

"I'm not going to say there wasn't any doubt," Bumgarner said. "It's tough to forget a start like that, but I tried to put it behind me. I was always taught to feel doubt and (succeed) anyway. That's what I did."

Bumgarner made one physical adjustment, saying he kept his eyes focused on Stewart's mitt rather than looking away and then returning his gaze to the target.

His biggest out might have been the first, when Mickey Brantley started the game with a line drive that required a running catch by right fielder Nate Schierholtz. Bumgarner allowed a hit in the inning, but no more.

He pitched a shutout fourth despite inning-opening singles by Orlando Cabrera and Asdrubal Cabrera. Even the sixth-inning run he allowed was aided by a disputed "fair" call from home-plate umpire Jerry Layne on Orlando Cabrera's shot past third. There was no third-base ump after Hunter Wendlestedt, the original home-plate ump, took a foul tip to the mask and left the game.

Cabrera's double sent Brantley to third with nobody out. Brantley scored on an infield out, but Bumgarner struck out Carlos Santana and Grady Sizemore to preserve a 3-1 lead.

"I don't know if that ball was fair or foul," Bochy said. "What's important was the way Madison handled it. Second and third with nobody out, and he only gave up one run."

Bumgarner (4-9) got his final three outs with strikeouts in the seventh, earned his second career win at AT&T Park and gave the Tribe's Fausto Carmona (4-10) the honor of being the majors' first double-digit loser.

Pablo Sandoval singled and doubled but left with a tight quad muscle. He expects to play Tuesday, when the Giants play a doubleheader against the Cubs in Chicago.